Cellulose-ether film and composition for making the same



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s'rnwezar J. CARROLL, or Rocniasrnn, new YORK, ASSIGNOR T EASTMAN KODAK COMPANY, or nocnnsrnannw vonx, aoonronerron on NEW YORK.

No lir awingf To aZZrwhom it mag concern:

- Be it known'that I, STEWART abimtt,

' a citizen of the United States of America,

residin roe and State ot-New York, have invented certain new and useful Improvements in films andcompositions for making thefsame.

One object of the invention is to provide films in which the flexibility is. maintained even undersevere conditions, such as pro longed heating. Another object of the in- A vention is .to provide a flowable film-forming composition which will be stable and will produce films which will likewise be stable and maintain their flexibility." Other ob jects will hereinafter appear.

v in U. s. Patent No. 1,188,376, Lilienield j June 20,1916, there are disclosed a series of alkyl ethers of cellulose. Certain of these are practically insoluble in Water, and'tlie present invention relates primarily, to ethers having that property, although it'is not re stricted -to them. When such ethers are made into films for different purposes, such as photographic supports or protective coatings, it is desirable, under circumstances which are often met with in practice, that they withstand prolonged heating without becoming brittle. In testing such films to determine whether they will withstand the conditions otpractice, severe testsare customarily made by heating them for several weeks at a temperature of 65 C. It is desirable that the films remain flexible even after twelve weeks of'continuous heating at the above temperature.

I have discovered that films which maintain their flexibility under the above described conditions may beprepared by incorporating resorcinol therein. Moreover, the required proportion of this stabilizer is comparatively small, thereby lessening'the expense of usingit. It is incorporated with the cellulose ether by the aid of a common at'Rochester, inthe county of Mon- Cantonese-Earner. FILE-nun GOMPOSITIOLT non MAKING THE'SAME.

it Application filed February 243.1923. Serial No. 621,090.

solvent, the resulting solution or' dope being flowed or deposited and the films formed by evaporation of the volatile. ingredients in the Way" understood by those skilled in the art. Being of high boiling point and consequent low'volatility, resorcinol remains in the final film in a useful proportion.

For example, I may dissolve 20 parts by' weight of celluloseether, say water-i11solu-.

ble ethyl cellulose, and 2 parts of resorcinol in 140 .parts of a volatilesolvent mixture,

say methyl acetate and methyl alcohol. The

ratio' (pt-methyl acetate to methyl alcohol may, of course, vary, 126 parts of the former to 14 parts of the latter being useful. The

percentage.ofcellulose ether can, of course,

be varied also, as'well as the quantity of stabilizer. Where thin films or" coatings are to be made by applying the composition as a.

lacquer or varnish, the amount of volatile solvent will be increased until the dope reaches thelrequired thinness, as willbe understood by those skilled in this art.

With the proportions given in the example a dope is produced which may be used in the preparation of films for photographic purposes in the apparatus and by the methods customarily eployed. The product is tough, flexible and transparent.

Films produced from the hereinabove described compositions contain sufficient stabilizer, such as resor'cinol, in combination with thefcolloidized cellulose ether to maintain their flexibility, even when they are heated for twelve weeks at 65 C. In practical use, where they are unlikely to meet any severer conditions, they maintain the necessary flexibility in a reliable way.

Resorcinol does not have'to be employed alone, butother substances may be added to the dope which impart additional properties to it, such, for instance, as triphenyl or tricresyl phosphate, monochlornaphthalene,

- volatile common solvent.

'3'. Asan article of manufacture, a) film comprising cellulose ether and a, stabilizer of resorcmol. o r

i. As an artlcle of manufacture, a tr'ahsv parent flexible film for use as a photographic 1 support "comprising water-insoluble ethyl cellulose and resorcinol.

Signed at Rochester, New York this 19th day of February, 1923.

STEWART CARROLL. 

